Warm air space heater with air circulating blower



May 24, 1949. c. M AFEE 2,470,938

' WARM AIR SPACE HEATER WITH AIR CIRCULATING BLOWER Filed July 17, 1944 Patented May 24, 1949 UNITED STATES ATE if OFFICE WARM AIR SPACE HEATER WITH AIR CIRCULATING BLOWER 2 Claims.

This invention relates to a circulatory heater, and more particularly to a heater drawing in air from a point near the floor, passing it in heat exchange relation with heating means and then projecting it horizontally.

One feature of this invention is that it provides an improved circulatory heater of the socalled room heater type; another feature of this invention is that it results in improved flow characteristics of the air being circulated, minimizing Stratification of air in the room or rooms and operating to keep the heat nearer the floor; yet another feature is that my improved heater achieves substantially greater projection of air, greater range of air circulation, with a blower or fan of given power; still another feature of this invention is that it provides a smooth change of direction of air flowing along the floor and up into the inlet at the bottom of the heater; a further feature of this invention is that it eliminates swirls and eddies in air entering the inlet of the heater; and still a further feature of this invention is the provision of an outer housing and an inner combustion chamber so constructed as to efi'ect all the desired changes of direction in air i flow gradually and smoothly, providing high emciency of air circulation. Other features and advantages of this invention will be apparent from the following specification and the drawings, in which:

Figure 1 is a front elevational view of one form of heater embodying my invention; Figure 2 is a side elevational view of the heater shown in Figure 1, looking from the left of that figure; Figure 3 is a horizontal sectional view along the line 33 of Figure 2; and Figure 4 is a vertical sectional view of the heater, from front to back.

Circulatory heaters are finding increased favor in the field, such heaters sometimes being called room heaters, although actually they are capable of heating several rooms, if properly located. These heaters include an outer housing or shell,

' as it is sometimes variously termed, having an air inlet opening and an air outlet opening, with heating means inside. Air enters the inlet opening, passes in heat exchange relation with the heating means and then is projected out of the outlet, forced circulation or projection of the air being eifected by a blower or fan which may be located at any convenient point within the housing, preferably near the inlet. Circulatory heaters of the kind heretofore conventionally in use have had relatively poor air circulation efliciency, and I have discovered that one of the biggest factors in thispoor circulation e iiiciency is the creation of swirls and eddy currents in the air immediately beneath the blower in the inlet. In addition, poor design of the interior of the housing, and of the combustion chamber, has resulted in still further decreasing the efliciency of air circulation.

I have devised and am here disclosing and claiming an improved circulatory heater which overcomes these and other objections of prior circulatory heaters. I have found it highly desirable to project the heated air horizontally and relatively close to the floor, with the center of projection preferably about 1 /2 or 2 feet from the fioor, as this gets the heat down closer to the floor and results in much greater comfort to the occupants of the room. Moreover, proper design of the heater to provide a smooth flow of air back along the floor as a return circulation path, and up into the heater inlet without swirls or eddies, minimizes stratification of air of different temperatures in the room, and provides increased range of projection with a blower of the same power. My improved air circulation is principally the function of a balile arrangement located beneath the air inlet opening at the bottom of the heater; although the action of this bafile arrangement is supplemented and air circulation further improved by the streamlined design of the interior of the heater housing, and of the exterior of the combustion chamber or heating means, and baffies at the outlet which assure complete control of air direction.

Referring now more particularly to the particular embodiment of this invention illustrated in the drawings accompanying this application, a heater embodying my invention is shown as having an outer housing or shell identified in general as l6 and an inner heating means in the form of a closed combustion chamber H. Any conventional fuel, as gas or oil, is burned in the burners l2 at the bottom of the combustion chamber, the hot products of combustion traveling straight up the front of the chamber, direct radiation being permitted through a Pyrex front portion Ila, until they reach the top of a baiile lib intended to prevent unduly rapid exit from the chamber, the products of combustion then passing into a rear portion of the combustion chamber and out a fiue pipe IS. The surface Ha. serves to provide direct radiation of heat through the front or outlet opening of the housing; and the remaining walls of the combustion chamber, and the portion of the fiue pipe withinthe housing, serve as heat exchange surfaces between the products of combustion and air being circulated through the housing.

The housing is provided at its lower end with a central opening which may, for example, be about twenty by thirty inches. This opening, hereinafter termed the inlet opening, is preferably spaced four to six inches above the floor, and a blower or fan comprising the blades l4 driven by a motor l5 serves to assist the natural gravity circulation in drawing air through the removable filter l6, andvproviding the desired forward projection of air. The ihousing is provided on its front wall with a large rectangular outlet opening, the effective outlet area being preferably less than that of the inlet, heat passing out through this opening both as heated air and asheat radiated directly from the front of the combustion chamber l i.

As may be best seen from an examination of Figure 4, the combustion chamber is so constructed and arranged within the housing ill that, while about a quarter of the air entering the inlet openingmoves to the right and directly toward the outlet (speaking with respect to the pos ition of the parts ,as viewed in Figure 4), aboutthree quar-ters of the air travels up to theleft or behind'the combustion chamber ll,

over the top thereof, and then out the outlet opening. This air is in good heat exchange contact with the walls of the combustion chamber, and of the flue pipe [3,,duringgthis rather protracted passage of travel through the housing, so that it is heated substantially before, being v projected out into the room. The provision of rounded corners on the combustion chamber, the gradually sloping upwardly extending wall I I0 inthe back thereof, and the provision of curved inner corners glilaand fllb at the top of thehousing, with the front of the housing slightly higher than the rear thereof, ensures a smoothv ilow path forthe air with gradual changes in direc- -tion providing-the greatest efficiency of air movement throughthe-heater housing. The louver :Hi-c prevents pocketing of ,air in the front corner of the housing. In order to prevent swirls and eddies in the front of the combustion chamber as the air is leaving the outlet, the movement of the air is further directedby a pair of curved bafiles or louvers 18a and 18b on the-front of the combustion chamber and serving to change the direction of air comingup from the bottom or down from the top into a horizontal direction of travel.

Where the return circulation path for .projected air is along the floorand back to the bottom .of the heater from all directions, I have found that 'the sudden change in direction of air fromhorizontal to vertical, and the action of the rotating blades l 4, would create highly undesirable swirls and eddies in the air flow immediately. beneath the fan. In order to prevent this I provide a baffle arrangement beneath theheater here shown as comprising four metal I9e immediately at the floor,.as may be best seen inFigure 4. These triangles, moreover, are smoothly and gradually curved in one plane, as may also be best seen in Figure 4. Regardless of the direction of approach of air therefore, air moving horizontally alongthe; floor has its direction of moveme d ally and, sm ot c a e y the curved baflle arrangements, so that its entry into the inlet, of the heater and its subsequent forcedcirculation by the fan 'bladesqld is witha out loss of efficiency due to abrupt changes in direction. In order to prevent swirls and eddies in the air entering this inlet, I provide vertically extending sheet metal partitions Zlla-d at the junctions of the triangular portions and extending up from these triangular bafiie portions to the base of the heater.

The placement of the air inlet in the bottom of the heater housing and; spaced several inches above thefioor, the associationof the inlet with the bafile arrangement just described above, the construction and arrangement of the combustion chamber and of the housing, or in particular the top thereof, and the arrangement of the air outlet opening with the baffles [8a and 1817 results inmuch more efllcient air circulation for a given power of the motor I 5. That is, the combination and arrangement just described provides horizontal projection of the warm air at a level relatively quite close to the floor and to a distance about 25% further than the range of air projection of conventional heaterswith the same power blowers. This, coupled with maximum utilization of heat in the combustion chamber by good heat transfer to the air, i n cluding utilization of a much larger portion of the flue pipe l3 as a heat transfer means than has heretofore been used,through the provision of the grommet or,b0ss 25, results in considerablyimprovedand more efiicient heating fora given rateoffuel and electric power consumption.

Inaddition, I have provided an improved humidifying device so arranged as toQenable adjustment of the rate of water evaporation very conveniently. As may bebestseen in Figure i, this comprise a trough 22 at theback of the heater, this trough being of generally triangular shape in cross section and being pivotally mounted at its base. Adjustment means, in. the form of a pivoted latch bar 22, enables the trough to be located fully within the housing as illustrated, to provide maximum evaporation orp artially or entirely outside of the housing toprovide various ratesof water, evaporation. Thieparticular feature is not claimed. hereafter, asit forms the subject matter of anothercopending application moreparticularly directed thereto] While I have shown and described cert ain..e m-

. bodiinents of my invention itis tofbe understood that it is capable of many modifications.

. Changes, therefore, in ,the .constructionand arrangement may be made without departing from the spirit and-scope of theinvention as disclosed in the appended claims.

I claim:

1. In a circulatory heater comprising a,ho usi.ng having means adapted to support the housingiin .spaced relation to ajfioor upon which .theh'eater is adapted to be supported, said housing having a downwardly facing inlet opening .in, its. bottom near the-floor, said housing having an air,.out l et opening, heating means located within thehousing, and a blowerfor' drawing air in,s aid. inl et, passing it in-heat exchange r'elation. ,.with-,the

heating means, and forcingit outsaid. air outlet opening, air flow guiding means including: ba tle means between the .floorandesaid inlet openip this bafile means including aplurality oftgene ally triangular portions curvedinwardlyand upwardly for effecting a gradual and s moothchangeliin direction of air moving along the floor, aifid jljlto the inlet, these triangular portions having th eir apices meeting at alpoint adjacent the cepter of t housi n the r low an broad flra i ent he o up hicht e dev se res s st parallel thereto, and a plurality of vertical partition portions for preventing swirls of air beneath said inlet, these partition portions extending up from the junctions of the sides of adjacent triangular portions, said baflie means being adjacent the housing supporting means and directly below said inlet opening.

2. In a circulatory heater comprising a housing having means adapted to support the housing in spaced relation to a floor upon which the heater is adapted to be supported, said housing having a downwardly facing inlet opening in its bottom near the floor, said housing having an air outlet opening in one side thereof, heating means located within the housing, and a blower for drawing air in said inlet, passing it in heat exchange relation with the heating means, and forcing it out said air outlet opening, air flow guiding means including: baflie means between the floor and said inlet opening, this baflie means including a plurality of generally triangular portions curved inwardly and upwardly for efiecting a gradual and smooth change in direction of air moving along the floor and into the inlet, these triangular portions having their apices meeting at a point adjacent the center of the housing and their lower REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,798,290 Winner Mar. 31, 1931 1,861,812 Modine -1 June 7, 1932 2,001,531 Hall May 14, 1935 2,223,178 Le Fevre Nov. 26, 1940 2,237,569 Lofgren Apr. 8, 1941 2,258,731 Blumenthal Oct. 14, 1941 2,312,123 Place Feb. 23, 1943 2,352,485 Kritzer June 27, 1944 

